Molecular characterization of an anion pump. The arsA gene product is an arsenite(antimonate)-stimulated ATPase.

摘要: Abstract The products of the arsenical resistance operon plasmid R733 form an efflux system for arsenicals. Detoxification results from active oxyanions, preventing their concentration reaching toxic levels. largest polypeptide encoded by ars was purified. From N-terminal sequencing purified protein, termed ArsA shown to correspond product arsA gene. protein demonstrated bind ATP two methods. First, a photoadduct with [alpha-32P]ATP formed irradiation at 254 nm. Second, bound fluorescent analogue, 2',3'-o-(2,4,6)trinitrophenyl ATP, half-maximal affinity 2 microM. By both assays competition observed or ADP, but not AMP, GTP, CTP, UTP. In nucleotide binding assays, Mg2+ required, neither arsenite nor antimonate had any affect. contrast, exhibited ATPase activity which dependent on presence antimonate. suggest that is catalytic subunit oxyanion-translocating ATPase.